According to the Encarta Dictionary, the definition of biodiversity is "the range of organisms present in a particular ecological community or system. It can be measured by the numbers and types of different species, or the genetic variations within and between species." When I think of biodiversity, I think of the plant and animal life that thrives in the desert ecosystem or that of the artic sea, even though I know biodiversity is in every ecological system.
The desert ecosystem consists of many life forms; much more than I thought could live in such a harsh atmosphere. The same goes for those in the artic sea; it actually has an ice specific ecosystem, which consists of bacteria, viruses, unicellular algae, diatom chains, worms and crustaceans. The ice specific ecosystem is used by warm-blooded animals such as seals, birds, polar bears, and whales for migration routes, hunting areas, rookeries, and protection for raising their offspring. (Krembs C., Deming J. 2008)
Now, I am going to venture into some species and the unintentional man made path ways that made them go out of their element. When the west was first settled and the natural habitats were converted to farm and ranch land many animals were displaced such as the deer, elk, moose and bison.( http://www.amnh.org/nationalcenter/Endangered/) These animals were forced to disperse causing a reduction in their numbers and a change in their habitat. The Northern spotted owl is another such victim, with the continuous logging of it's forests.
The Purple Loosestrife is a perfect example of the use of not only natural pathways, but also unintentional man-made pathways. This plant is a native to the wetlands of Asia and Europe, it was originally intended as a decorative plant, but ended up being a nuisance, it appeared in the Great Lakes Area in 1869 and later in Illinois. This plant traveled by it seeds beings spread by moving water and animals of the wetlands (natural pathways). The Purple Loosestrife is also spread when seeds get away from nurseries and gardens (unintentional man-made pathway). In Wisconsin, Illinois, and Minnesota, and Indiana the planting of this plant is banned and it has been deemed a "noxious weed". (Illinois Department of Natural Resources)
The Zebra Mussel is another example of an unintentional man- made pathway. The Zebra Mussel originates from the Caspian Sea area in Asia. In 1986, it was unintentionally brought over from Europe by ship. This Mussel was not a welcome species to the Great Lakes or other rivers and lakes. Between 1989 and 1995, approximately 70 million dollars were spent in repairs to power plants and industrial facilities that were caused by Zebra Mussels attaching themselves to water intake pipes.
Biodiversity is in crisis for three different reasons, the first and biggest reason is habitat destruction as with the Northern spotted owl. The second reason is the introduction of exotic species such as with the overgrown Purple Loosestrife that does not offer food or cover for the animal's native to the wetlands. The third reason is overexploitation as with the American Bison.
Biodiversity needs are not only those of emotional or ornamental they are also for our livelihood. It is through other species that we rely on our oxygen, food, medicines, and clothing.
Campbell, N., Reece, J., & Simon, E. (2007). Essential biology with physiology, 2nd edition.(pp.450-455)San Francisco, CA: Pearson.
Illinois Department of Natural Resources, Aquatic Illinois-Exotics , Retrieved May 31, 2008, from http://dnr.state.il.us/lands/education/CLASSRM/aquatic/UNIT_3B.PDF
Krembs C., Deming J. (2008) Artic Theme Page, Sea ice: a refuge for life in polar seas?, Retrieved May 31, 2008, from http://www.arctic.noaa.gov/essay_krembsdeming.html
American Museum of Natural History (1996) Endangered: Gray Wolf. Retrieved May 31, 2008, from http://www.amnh.org/nationalcenter/Endangered/